An experimental investigation on the correlation between testing cycles and delamination of plastic ball grid array packages under thermal cycling with high humidity

An experimental investigation is presented in this paper to correlate the progressive growth of delamination in plastic ball grid array (PBGA) packages to the number of testing cycles. The specimens were placed in an environmental chamber under the testing conditions specified by JEDEC-STD-22 TM-A-104. C-mode scanning acoustic microscopy (C-SAM) was used to inspect the delamination inside the specimens. The specimens were retrieved from the chamber every five days for ultrasonic inspection. The development of delamination with respect to the elapsed testing cycles could be clearly observed. It was found that the delamination occurred at the interface between the die and the BT substrate. More than 80% of delamination was observed at the die-attach area after 35 days of thermal cycling.